Theoretical study and experimental investigation of a Helmholtz-type gas-fired pulse combustor are presented. In this study, a mathematical model was developed to evaluate the operating frequency of the pulse combustor. A variety of experiments were also performed to prove the validation of theoretical frequency model and compare the theoretical frequency with the experimental one. In the experiments, the length and diameter of the tail pipe, the volume of the combustion chamber and the gas supply pressure of the combustor were changed within certain limits. In the experiments, related to tailpipe length, there was a perfect agreement between the tailpipe lengths of 1.2 and 1.6m. As the theoretical frequency was compared with the experimental one, the maximum deviation was 5.8 Hz (1.25% errors). If the frequency comparisons related to the volume of the combustion chamber were taken into consideration, the calculated frequency and measured ones agreed very closely. In the volumes between 1/2 V-c and V-c, maximum deviation was 5.4 Hz (7.7% errors). In this study, a tunable pulse combustor, which is used for increasing the frequency of industrial processes, was also developed. Copyright (c) 2005 John Wiley I Sons, Ltd.